Abstract: A method of sealing a hole in a wall of a hollow structure comprises providing a sealed chamber that is external to the structure and that is in fluid communication with an internal space of the structure via the hole. The structure may be a pipe-in-pipe structure and the internal space may be an annulus between outer and inner pipes. Fluid flows through the hole into or out of the chamber as the pressure and/or composition of fluid in the internal space is adjusted. Then, a plug is spun and friction-welded into the hole. The plug is inserted into the hole from within the chamber.

Abstract: A method of joining together liner sections within a polymer-lined pipe energises an induction coil inside the pipe to spot-heat part of a circumferential interface between the liner sections. This melts and fuses the polymer material locally. The induction coil is then moved along the interface to heat other parts of the interface successively above the melting temperature. An apparatus for performing the method has a power supply for energising the induction coil and a drive system for moving the energised induction coil relative to a body of the apparatus. The apparatus may be configured as a carriage that is movable along the pipe.

Abstract: A method of joining together liner sections within a polymer-lined pipe energises an induction coil inside the pipe to spot-heat part of a circumferential interface between the liner sections. This melts and fuses the polymer material locally. The induction coil is then moved along the interface to heat other parts of the interface successively above the melting temperature. An apparatus for performing the method has a power supply for energising the induction coil and a drive system for moving the energised induction coil relative to a body of the apparatus. The apparatus may be configured as a carriage that is movable along the pipe.

Abstract: A liner sleeve is secured within a host pipe of a bimetallic lined pipe by driving a spinning friction stir welding tool through the liner sleeve but not through the full wall thickness of the host pipe. This forms a thermo-mechanically affected welded zone in which metal of the liner sleeve is bonded with some metal of the host pipe. Relative movement between the spinning tool and the lined pipe extends the welded zone along a weld path. Where the pipe is mechanically lined, the welded zone extends along a previously unbonded outboard region that extends longitudinally from an inboard region at which the liner sleeve is bonded mechanically to the host pipe.

Abstract: A method of sealing a hole in a wall of a hollow structure comprises providing a sealed chamber that is external to the structure and that is in fluid communication with an internal space of the structure via the hole. The structure may be a pipe-in-pipe structure and the internal space may be an annulus between outer and inner pipes. Fluid flows through the hole into or out of the chamber as the pressure and/or composition of fluid in the internal space is adjusted. Then, a plug is spun and friction-welded into the hole. The plug is inserted into the hole from within the chamber.

Abstract: A method of sealing a hole in a wall of a hollow structure comprises providing a sealed chamber that is external to the structure and that is in fluid communication with an internal space of the structure via the hole. The structure may be a pipe-in-pipe structure and the internal space may be an annulus between outer and inner pipes. Fluid flows through the hole into or out of the chamber as the pressure and/or composition of fluid in the internal space is adjusted. Then, a plug is spun and friction-welded into the hole. The plug is inserted into the hole from within the chamber.

Abstract: A method of joining together liner sections within a polymer-lined pipe energises an induction coil inside the pipe to spot-heat part of a circumferential interface between the liner sections. This melts and fuses the polymer material locally. The induction coil is then moved along the interface to heat other parts of the interface successively above the melting temperature. An apparatus for performing the method has a power supply for energising the induction coil and a drive system for moving the energised induction coil relative to a body of the apparatus. The apparatus may be configured as a carriage that is movable along the pipe.

Abstract: A method of sealing a hole in a wall of a hollow structure comprises providing a sealed chamber that is external to the structure and that is in fluid communication with an internal space of the structure via the hole. The structure may be a pipe-in-pipe structure and the internal space may be an annulus between outer and inner pipes. Fluid flows through the hole into or out of the chamber as the pressure and/or composition of fluid in the internal space is adjusted. Then, a plug is spun and friction-welded into the hole. The plug is inserted into the hole from within the chamber.

Abstract: A method of making mechanically-lined pipe with primary expansion by plastically expanding a liner sleeve within an outer pipe, under lining pressure applied internally to the liner sleeve. On relieving the lining pressure, elastic radial contraction of the outer pipe makes a mechanical bond between the outer pipe and the liner sleeve. Then, secondary expansion of the outer pipe is performed under fixing pressure, which may be greater than the lining pressure, applied internally to the liner sleeve at an end portion of the pipe. This makes or strengthens a mechanical bond at the end portion. The resulting pipe joint has an end portion and a body portion inboard of the end portion. The body portion has a first, lesser bonding pressure between the outer pipe and the liner sleeve. The end portion has a second, greater bonding pressure between the outer pipe and liner sleeve.

Abstract: A method of using friction stir processing to repair a defect in a pre-existing weld of a pipeline of steel or other ferrous alloy. The method comprises attaching run-on and run-off tabs to the pipeline on respective sides of the defect and then advancing a friction stir processing tool into the nm-on tab. The tool is moved from the nm-on tab to the run-off tab along a weld-processing path that incorporates the defect. Once the defect is repaired, the tool is removed from the run-off tab. The run-on and run-off tabs may then be removed from the pipeline. The nm-on and nm-off tabs are generally wedge-shaped, each comprising an inner seating face and an outer running face that converges with the inner seating face. When attached to the pipeline, the tabs toward each other about the circumference of the pipeline.

Abstract: A method of fabricating a metal pipeline by friction stir welding (FSW) along a circumferential interface includes spinning first and second FSW tools about respective axes of rotation in contact with a pipe wall to heat, plasticize, and stir respective zones of plasticized metal at the interface. The zone of plasticized metal produced by the second FSW tool extends deeper into the pipe wall than the zone of plasticized metal produced by the first FSW tool. Relative circumferential movement of the FSW tools along the interface is controlled such that the second FSW tool following the first FSW tool enters the zone of plasticized metal produced by the first FSW tool while the metal in that zone remains plastic.

Abstract: A method of fabrication by friction stir welding (FSW) at an interface between adjoining components such as pipe lengths of a pipeline has layers of different metals on each side. FSW is performed from one side of the adjoining components by effecting relative movement of a first FSW tool along the interface. FSW is performed from an opposite side of the adjoining components by effecting relative movement of a second FSW tool along the interface. Advantageously, FSW is performed simultaneously from both sides of the adjoining components with the FSW tools applying loads in mutual opposition about the adjoining components.

Abstract: A method of making mechanically-lined pipe with primary expansion by plastically expanding a liner sleeve within an outer pipe, under lining pressure applied internally to the liner sleeve. On relieving the lining pressure, elastic radial contraction of the outer pipe makes a mechanical bond between the outer pipe and the liner sleeve. Then, secondary expansion of the outer pipe is performed under fixing pressure, which may be greater than the lining pressure, applied internally to the liner sleeve at an end portion of the pipe. This makes or strengthens a mechanical bond at the end portion. The resulting pipe joint has an end portion and a body portion inboard of the end portion. The body portion has a first, lesser bonding pressure between the outer pipe and the liner sleeve. The end portion has a second, greater bonding pressure between the outer pipe and liner sleeve.

Abstract: A method of fabricating a metal pipeline by friction stir welding (FSW) along a circumferential interface includes spinning first and second FSW tools about respective axes of rotation in contact with a pipe wall to heat, plasticize, and stir respective zones of plasticized metal at the interface. The zone of plasticized metal produced by the second FSW tool extends deeper into the pipe wall than the zone of plasticized metal produced by the first FSW tool. Relative circumferential movement of the FSW tools along the interface is controlled such that the second FSW tool following the first FSW tool enters the zone of plasticized metal produced by the first FSW tool while the metal in that zone remains plastic.

Abstract: A method of fabrication by friction stir welding (FSW) at an interface between adjoining components such as pipe lengths of a pipeline has layers of different metals on each side. FSW is performed from one side of the adjoining components by effecting relative movement of a first FSW tool along the interface. FSW is performed from an opposite side of the adjoining components by effecting relative movement of a second FSW tool along the interface. Advantageously, FSW is performed simultaneously from both sides of the adjoining components with the FSW tools applying loads in mutual opposition about the adjoining components.